A 10-year-old disabled boy was stuck inside a locked bus for six hours at a depot near Wollongong before he was discovered by the driver.
The boy was travelling to Peterborough School in Warilla on Thursday morning when he apparently failed to leave the vehicle, which the driver returned to a depot and locked.
He was only discovered when the driver returned to the bus at 2.45pm, police told AAP on Friday.
The school was notified and called paramedics, who assessed the child and deemed him unharmed.
"The child was in the care of staff at Peterborough School and was returned home to his family after the ambulance assessment," a NSW Education Department spokesman said in a statement.
The Assisted School Travel Program and Employee Performance and Conduct Unit are investigating the NSW incident.
The driver has been suspended pending an inquiry.